Rotating seals for cell processing systems

ABSTRACT

The invention provides an improved rotating seal apparatus including a plurality of concentrically spaced annular rotating seals. The invention also provides a rotating seal apparatus including a pressurized annular chamber surrounding an annular rotating seal.

RELATED APPLICATION

This application is a continuation of Ser. No. 09/081,733 filed May 20,1998, now abandoned, and claims the benefit under Title 35. U.S.C.§119(e) of pending U.S. Provisional Application Serial No. 60/047,213,filed May 20, 1997 entitled “Cell Processing System”, incorporatedherein by reference. This application is also related to co-pending U.S.Patent Applications entitled: “Apparatus and Method for Expressing FluidMaterials”; (Ser. No. 09/082,200); “Fluid Management Systems”(Ser. No.09/082,201); “Optical Sensors for Cell Processing Systems”(Ser. No.09/082,086); and “Cell Processing Systems”(Ser. No. 09/082,341), all ofwhich are incorporated by reference.

FIELD OF THE INVENTION

The invention relates to rotating seals for centrifugal devices useful,inter alia, in cell processing or cell washing applications.

BACKGROUND OF THE INVENTION

Generally, cell processing requires steps in which cells or cellelements are separated from a liquid phase. This separation is typicallyaccomplished by centrifugation. The sterility of the cells beingprocessed is protected by the incorporation of a dynamic seal betweenrotatable and stationary centrifuge elements, referred to as a “rotatingseal”. In addition to deterring the entrance of microbes into thesterile environment of the processing apparatus and the biologicalmaterials contained therein, a rotating seal ideally minimizes theleakage of air and frictional heating and is capable of tolerating mildto moderate misalignment and vibration.

A number of designs for rotating seals have been developed. For example,U.S. Pat. No. 3,489,145 by Judson et al. discloses a lower rotatingelement that forms a seal with an upper stationary element, and that hasa central bore extending throughout. U.S. Pat. Nos. 3,409,203 and3,565,330 by Latham disclose rotating seals formed from a stationaryrigid low-friction element in contact with a moving rigid element and anelastomeric element which provides a resilient static seal as well as amodest closing force between the seal surfaces. U.S. Pat. No. 3,801,142by Jones et al. relates to a pair of elements having confronting annularfluid-tight sealing surfaces maintained in a rotatable but fluid-tightrelationship by axial compression of a length of elastic tubing. In the“B. T. Bowl” marketed by Bellco (Mirandola, Italy), a rotating seal isformed between a ceramic ring element attached to rotatable elements ofa centrifuge and a fixed graphite ring attached to stationary centrifugeelements; an elastomeric diaphragm is attached at one end to an adapterring for the graphite ring and at the other end to a stationary part ofthe centrifuge. U.S. Pat. Nos. 4,300,717 and 5,045,048 by Latham, Jr.relate to a rotating seal which has been modified by the incorporationof recessed areas contiguous with “sealed” regions; the recessed areasare in communication with the external environment and are used toentrap and expel extraneous particles which may form duringcentrifugation.

In the field of centrifugal cell washing, two technologies currentlydominate the state of the art, as exemplified by the Cobe 2991 and theHaemonetics Model 115 cell washers. Both systems employ a set ofrotating seals to contain the fluids in the disposable rotatingcontainers. These seals have been classified by the FDA as “open”devices for the purpose of washing red blood cells, in that the sealshave not yet been validated as having the ability to satisfactorilyprevent biological contamination of the sterile interior under allrunning and handling conditions. According to the American Associationof Blood Banks (“AABB”) standards, “when glycerolizing ordeglycerolizing involves entering the container, the system isconsidered ‘open’ and the resulting suspension of deglycerolized cellscan be stored for only 24 hours at 1-6 degrees Centigrade.” This 24-hourstorage shelf life after deglycerolization, and other factors (includingcost), make the foregoing systems less useful for routine inventorymanagement and relegate them primarily to specialty uses such as storingrare blood types, autologous donations, or battlefield applications forthe Navy.

None of the foregoing rotating seals provides a seal which permits thestorage of processed biological materials such as red blood cells forextended period of time. The foregoing seals do not provide adequateprotection from the contamination of processed biological materials bymicrobial contaminants.

SUMMARY OF THE INVENTION

The invention provides an improved rotating seal which provides enhancedanticontamination properties for use in particular in centrifugaldevices for processing biological materials. The seal of the inventioncomprises at least two concentrically spaced rotating seals, wherein theannular space between the seals forms at least one sterile chamber. Inthe event of a leak in one of the concentrically spaced rotating seals,the additional seal or seals act to maintain the sterile environment ofthe cell processing system by reducing or preventing microbialcontamination. In addition, the sterile annular chamber can bepressurized with a sterile supply of gas as a second means of reducingor preventing microbial contamination. The pressurized chamber acts as abarrier to prevent microbes from migrating into the interior of the cellprocessing system across a leaky seal. The pressurized chamber also actsas a barrier to reduce or prevent the migration of fluids or particulatematter from the interior of the cell processing system across the aleaky seal.

According to one aspect of the invention, an improved cell processingsystem is provided, the improvement comprising a plurality of annularrotating seals between rotating and non-rotating portions of the cellprocessing system. The plurality of annular rotating seals define atleast one annular space between the annular rotating seals. The at leastone annular space is constructed and arranged for receiving pressurizedgas. In some embodiments, the plurality of annular rotating sealsincludes a plurality of sealing members defining annular sealingsurfaces which form a plurality of concentrically spaced annularrotating seals, the annular rotating seals defining at least one annularspace. At least one of the sealing members defines a channel in anon-sealing surface, which channel is in gaseous communication with theat least one annular space. Preferably the at least one annular space ispressurized with gas. In certain preferred embodiments, the annularsealing surfaces are substantially planar. In other embodiments, theapparatus also includes a body defining a gas port, wherein the gas portis in gaseous communication with the channel. The apparatus also caninclude a pressure sensor in communication with the gas port formonitoring the gas pressure in the annular space.

According to another aspect of the invention, a seal apparatus isprovided. The seal includes plurality of annular seal members. A firstannular rotating seal member includes a sealing face which defines aplurality of concentrically spaced annular sealing surfaces, and anaxial opening. A second annular rotating seal member has a sealing facewhich defines at least one annular sealing surface, and an axialopening. The first annular rotating seal member and the second annularrotating seal member are axially aligned and the annular sealingsurfaces are placed in contact to form a plurality of spaced apartseals. Preferably the annular sealing surfaces are substantially planar.In certain embodiments, the sealing face of the first sealing elementfurther defines an annular space between the annular sealing faces. Theannular sealing surfaces can be biased together by a bias element, whichpreferably is an elastomeric spring element. The annular sealingsurfaces are preferably formed of a material selected from the groupconsisting of ceramics, carbon phenolic and equivalent carbon compositematerials; more preferably, all annular sealing surfaces are formed ofceramic materials. In other embodiments, at least one of the non-sealingfaces of the first annular rotating seal member and the second annularrotating seal member define a channel in gaseous communication with theannular space.

The seal apparatus also can include a body which includes a first portdisposed in the axial openings of the first and second annular rotatingseal members. Preferably at least one of the non sealing faces of thefirst annular rotating seal member and the second annular rotating sealmember define a channel in gaseous communication with the annular space,wherein the body includes a gas port in communication with the channel.The seal apparatus also includes in some embodiments a base having anaxial opening and a processing container having a top defining an axialopening. The base is mounted in axial alignment on the top of theprocessing container, and the second annular rotating seal membermounted in axial alignment on the top surface of the base. Thusassembled, the first port of the seal apparatus is in fluidcommunication with the interior of the processing container. Preferablythe first port extends through the axial openings of the first andsecond annular rotating seal members and the base. The body also caninclude a fluid port in fluid communication with the space defined bythe first port, the first and second annular rotating seal members andthe axial opening of the base. In additional embodiment, the sealapparatus includes an outer shield defining a space between the outershield and the body, the base and the first and second annular rotatingseal members. Preferably the outer shield comprises a shield top, ashield bottom and a shield clamp, wherein the shield top is releasablymounted on the shield bottom, and wherein shield bottom and shield clamphave overlapping flanges which form a serpentine seal. In certainembodiments, the diameter of the shield bottom is smaller than thediameter of the shield clamp, the shield bottom has outwardly directedflange, and the shield clamp has an overlapping inwardly directedflange.

The seal apparatus also includes in certain embodiments an elastomericspring element disposed between the shield top and the body, wherein theclamp is movable between a first position and a second position whereinthe shield clamp is engaged with the base, wherein the spring element iscompressed when the shield clamp is in the second position.

According to yet another aspect of the invention, a method for sealing arotating processing container which rotates in a processing system isprovided. The method includes providing a stationary seal member mountedon a processing system, the stationary seal having a plurality ofcircumferentially spaced annular sealing elements. The method alsoincludes providing a rotating seal member mounted on the rotatingprocessing container, the rotating seal member at least one annularsealing element. The sealing elements of the stationary seal member andthe at least one sealing element of the rotating sealing member arecontacted to form a rotating seal between the rotating processingcontainer and the processing system.

According to another aspect of the invention, a method for sealing arotating processing container is provided. The method includes providinga plurality of annular seals between the rotating processing containerand a stationary portion of a processing system, wherein the pluralityof annular seals define an annular space. The annular space ispressurized to provide an improved seal for the rotating processingcontainer.

According to still another aspect of the invention, a method for heatingor cooling a sample during transport of the sample into or out of arotating processing container is provided. A seal apparatus including arotating seal and a port for transport of a sample to the rotatingprocessing container is provided, wherein the seal and the port define aspace in contact with the port. The space between the seal and the portis filled with a material having a temperature which is at or below thetemperature of the sample for cooling the sample, or a material having atemperature which is at or above the temperature of the sample forheating the sample. In preferred embodiments, the method provides forcooling of the sample by filling the space with waste materialsgenerated by the processing methods, the waste materials being at orbelow room temperature. In certain embodiments the method providescooling of the seal material during the transport of processing fluidsinto or out of the rotating processing container. The method includesproviding a seal having an annular-shaped inlet/outlet port in fluidcommunication with the processing fluids, and filling the annular spacedwith fluids that are cooler that the seal materials

In yet another aspect of the invention, a spring is provided. The springincludes a hollow elastomeric cylinder having bowed side portions. Thespring can be constructed of a certain height, width, thickness and sideportion arc to provide a constant biasing force upon compression of thespring. The compression of the spring concurrently changes the height,width and arc. In certain embodiments, the spring includes anelastomeric material of relatively thin cross-section which has ageometry that delivers a relatively constant force over a wide range ofdeflection values. Preferably the spring has a cross-sectional shapethat includes bowed side walls.

Thus the invention provides a seal apparatus including a plurality ofannular seals, and/or a seal apparatus including at least one annularseal and a pressurized annular space concentrically spaced apart fromthe annular seal. Methods of using the seal apparatuses for sealingrotating containers also are provided.

These and other aspects of the invention will be described in furtherdetail in connection with the detailed description of the invention.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view of an interactive cell processing system.

FIG. 2 is a conceptual flow diagram displaying operation of aninteractive cell processing system.

FIG. 3 is a block diagram of the interactive cell processing system ofFIG. 1.

FIG. 4 is a cross-section view of a centrifuge bucket and chuck whichdepicts the mounting of the rotating seal assembly in the centrifuge.

FIG. 5 is a perspective view of the exterior of the rotating sealapparatus.

FIG. 6 is a cross-section view of the rotating seal apparatus.

FIG. 7 is an exploded cross-section view of the rotating seal apparatus.

FIG. 8 is an exploded top perspective view of the rotating sealapparatus and processing container.

FIG. 9 is an exploded bottom perspective view of the rotating sealapparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The preferred embodiments of the invention are described with referenceto the drawings. Referring to FIGS. 1 and 3, an interactive cellprocessing system 10 includes a cell module 12, a supply module 20, afluid distribution module 40, a processing module 60, a collectionmodule 70 (not shown in FIG. 1) and a control module 80. These modulesare operatively interconnected for processing biological cells in asterile environment. Cell module 12 is constructed for a short term orlong term storage of biological cells for processing. Supply module 20includes several containers for storing different process chemicalsincluding saline, or other fluids used for washing the processed cellsand also includes sterile air. The containers are connected to fluiddistribution module 40 by a set of conduits. Fluid distribution module40 includes several valves and sensors for dispensing controlled amountsof the process chemicals from supply module 20 to processing module 60and for dispensing a known amount of the biological cells from cellmodule 12 to processing module 60. Furthermore, fluid distributionmodule 40 is constructed to direct the process waste from processingmodule 60 to a waste container 72 and the processed cells to a cellstorage container 74, both of which are located in collection module 70,while maintaining the purity and sterility of the cells. Control module80 directs the entire process according to a selected algorithm.

In general, the operation of cell processing system 10 is shown in FIG.2. Control module 80 executes a processing algorithm selected initially(98). Control module 80 includes a logic controller that receivesreal-time data from several in-line sensors arranged in a processingloop. A mass sensor (or a volume sensor) measures an initial amount ofthe provided biological cells (94) and sends the data to control module80. Control module 80 controls the amount of cells dispensed toprocessing module 60 in accordance with the processing algorithm. Basedon the provided amount of the biological cells, control module 80 alsocalculates the individual doses of the process chemicals (100) anddirects a set of control valves to dispense the chemicals (102) in aselected order to processing module 60, again in accordance with theprocessing algorithm.

Control module 80 executes iteratively the processing algorithm. Controlmodule 80 receives data from the individual sensors (e.g., a weightsensor, a volume sensor, a temperature sensor, an optical sensor, aresistance or capacitance sensor, a flow sensor, a pressure sensor oranother sensor arranged to monitor the transferred matter in a liquid,gaseous or solid state). After dispensing the selected amount of one orseveral processing chemicals to processing module 60, control module 80regulates the temperature and the time of processing and directs theprocessing module to agitate, mix or otherwise treat the cells with theprocess chemicals. Depending on the processing algorithm, control module80 may manage one or several processing cycles. At the end of eachcycle, processing module 60 may separate the processed cells fromintermediate products and from the process waste. During the separationprocess, fluid distribution module 40 detects the fluid component beingexpressed from processing module 60 and directs the separated componentsto different containers for disposal (110) or for storage (112). Eachprocessing cycle may use a different processing chemical and differentprocessing conditions. Cell processing system 10 can also processdifferent types of cells at the same time or sequentially. Furthermore,cell processing system 10 may also partially process biological cellsand then store them in cell storage container 74 (shown in FIG. 3),which may include a temperature control system. The processed cells maybe later automatically dispensed from cell storage container 74 andprocessed using another processing algorithm. The processed cells mayalso be grown in culture prior to another use.

Based on the starting weight of the biological cells, the controllercalculates the dosage of the processing chemicals. Supply module 20includes a weight sensor 29 for providing the weight of each processchemical to the controller. During the process, the controller confirmsthat correct amount of each process chemical has been transferred bymeasuring the change in the weight of the process chemical stored insupply module 20 and the initial weight of the chemical. The processchemicals in a fluid state are pumped through a 0.2 micron filter toassure sterility. A pressure transducer is mounted up-stream from thefilter. If the fluids being pumped through the filter have a variableviscosity, the controller will adjust the pumping speed to yield aconstant pressure drop across the filter membrane.

Processing module 60 is designed to assure identical processingconditions (e.g., pressure, temperature, mixing, processing time orother) for large and small amounts of the biological cells provided forprocessing. For this purpose, processing module 60 includes a processingchamber that has a variable volume design. Depending on the volume ofthe processed cells and other processing chemicals transferred into theprocessing chamber, the controller changes the chamber volume. Thevolume change is achieved by a movable wall that may be a membrane.Processing module 60 includes another pressure sensor for measuring thepressure inside the processing chamber and also includes a temperaturesensor for measuring the temperature inside the processing chamber.Based on the data from the temperature sensor, a heat transfer systemcan provide or remove heat from the processing chamber.

Cell processing system 10 may process or separate cells and/or cellelements from different liquids or solids. Such cells and cell elementsinclude, but are not limited to, erythrocytes (i.e., red blood cells);leukocytes (i.e., white blood cells, including lymphocytes,granulocytes, and monocytes); blood cell progenitors (e.g., primitivestem cells, burst forming units, reticulocytes, megakaryocytes, etc.);cell fragments (e.g., platelets, subcellular elements such as nuclei,debris, etc.); epithelial cells; endothelial cells; mesothelial cells;cells of normal tissues (e.g., liver cells, kidney cells, bladder cells,lung cells, pancreatic cells, embryonic cells, fetal cells, etc.); cellsof abnormal tissues (e.g., malignant cells), and so forth.

Referring again to FIG. 3, in one preferred embodiment of the cellprocessing system, cell module 12 includes a weight sensor 14 arrangedto weigh red blood cells provided in a bag 16. Tubing 17 connects bag 16to a leuko filter 18 and to fluid distribution module 40. Supply module20 includes a bag 21 with enzyme A1/B, a bag 22 with enzyme A2, a bag 23with 140 Molar potassium phosphate dibasic (DPP), a bag 24 withpolyethylene glycol (PEG), a bag 25 with storage solution, and a bag 26with phosphate citrate isotonic (PCI). Each bag is connected by tubing28 to fluid distribution module 40. Weight sensor 29 is constructed toweigh any of the above-mentioned fluids located in supply module 20.Supply module 20 also includes a compressor 30 connected via a filter 31and a check valve 32 to air reservoir 33, which stores sterile air usedfor cell processing. Pressure switch and sensor 34 is in communicationwith air tubing 36, which delivers sterile air to an air filter locatedin fluid distribution module 40. A regulator 37, connected to a solenoidvalve 36, regulates the air pressure provided to fluid distributionmodule 40 and to processing module 60. Fluid distribution module 40includes a peristaltic pump 42, and twelve plunger valves 43, 44, . . ., and 54 connected to a set of conduits for distributing the processchemicals and the cells during the automated process. The logiccontroller can close or open any combination of the twelve valves toredirect the fluid flowing inside the conduits. A pressure sensor 55measures the fluid pressure during the process, and a optical detector58 monitors the fluid to and from processing module 60. Processingmodule 60 includes a centrifuge 62 and an expresser system 64. Aninfra-red (IR) temperature sensor 68 monitors the temperature of theprocess chemicals or the cells located inside centrifuge 62. Collectionmodule 70 includes a waste bag 72, a saline solution bag 73, and aproduct bag 74. Collection module 70 also includes a weight sensor 76connected to product bag 76 and arranged to weigh the processed redblood cells.

The controller controls the volume of the processing chamber ofcentrifuge 62 to assure identical processing conditions for large orsmall amounts of the red blood cells. The processing chamber includes amembrane for containing expresser fluid. For small volumes, expressersystem 64 pumps expresser fluid into the chamber until the pressuretransducer at the chamber signals a full condition. This pre-fillingstep assures that different amounts of red blood cells are subjected tothe same accumulated centrifugal force and mechanical stresses due topacking. Otherwise, smaller amounts would spin longer and pack harder asthe expresser fluid fills the processing chamber during the expressionstep.

During the process, the controller receives input from IR temperaturesensor 66, which measures the temperature of the RBCs. If thetemperature is less than the set point, expresser of system 64 increasesthe temperature of the expresser fluid. Conversely, if the temperatureis greater than the set point, expresser of system 64 decreases thetemperature of the expresser fluid. A control loop continuously monitorsthe temperature of the processed cells.

Processing module 60 also includes a second pressure transducer thatmonitors the pressure of the sterile air on the rotating seal. If theseal is working, this pressure only fluctuates slightly betweenestablished limits. If the pressure drops below the establishedthreshold, a warning condition is initiated that calls for a check ofthe rotating seal as well as other possible causes of failure.

Expresser fluid system 64 included a third pressure transducer thatmeasures the pressure of the expresser fluid which is an indirectmeasure of the pressure on the red blood cells. The controller adjuststhe expresser pump speed to assure that pressure is within acceptedlimits and cells are protected from damage. If the pressure is too low,the pump rate is increased to speed up the expression cycle. If thepressure is too high, the pump is slowed down to protect the cells fromexcessive pressure. This also protects the seal from excessive pressureas well.

Optical sensor 58 sensor monitors the color and the turbidity of thetransferred fluids. Specifically, optical sensor 58 also monitors thesupernatant expressed from the centrifuge chamber. When red cells aredetected in the supernatant, the controller responds by stopping theexpresser pump to avoid losing any cells to waste or responds byswitching valves to collect the cells in a separate storage bagdepending on which cycle is being performed.

The cell processing system can be used, for example, in methods ofenzymatically converting blood type or inactivating pathogens. Certainmethods of enzymatically converting blood type are set forth in U.S.Pat. No. 4,330,619, 4,427,777 and 4,609,627 by Goldstein.

Processing module 60 includes a “rotating seal” that is a seal createdbetween moving and stationary components of the centrifugal element. Theseal acts as a barrier between the interior portion of the system inwhich processing occurs, which is desirably maintained as microbe-freeas possible, and a nonsterile environment which, at least during aportion of the operation of the system, is in communication with theenvironment external to the system. The rotating seal also prevents thedispersal of microbes (e.g. viruses) which may exist in a cell sampleinto the external environment.

The rotating seal comprises an upper element and a lower element,wherein one element rotates during at least a portion of the operationof the cell processing system. The rotating seal surrounds an axialopening through which cells and/or cell elements and processingmaterials are intended to pass during processing.

FIG. 4 is a cross-section view of a centrifuge bucket and chuck whichdepicts the rotating seal apparatus seated in the chuck. Protruding fromthe top of the centrifuge bucket are the first port 632, the headershield top 660 and the header shield bottom 650. The rotating sealapparatus is mounted to the chuck by mounts 686 protruding from the base680. The mounts mate with opposing projections fixed to the chuck,thereby transmitting the rotating force of the chuck to the lower partsof the rotating seal apparatus and the processing container to which thebase 680 is mounted.

FIG. 5 depicts an assembled rotating seal apparatus. The header shieldassembly is comprised of the shield top 660, the shield bottom 650 andthe shield clamp 670. The shield clamp includes an inwardly directedflange 672 which overlaps an oppositely directed flange on the shieldbottom. In alternative embodiments, the shield clamp can have a smallerdiameter than the shield bottom, and have an outwardly directed flangeto overlap an inwardly directed flange of the shield bottom. The shieldclamp is mounted on the base 680, which in turn is mounted on aprocessing container. As depicted in FIG. 6, the base 680 includes aflange 682 which includes a outwardly directed protrusion 684. When theshield clamp is mounted on the base, the protrusion 684 fits into theindentation 674 on the inside surface of the shield clamp, therebyholding the header shield assembly together and preloading the spring640 to create contact between the sealing surfaces. Ports 632, 634 and636 are included as inlets and outlets for materials passing through therotating seal apparatus to a processing container and for providingmaterials to internal portions of the rotating seal apparatus. These aredescribed in greater detail below.

Referring to FIGS. 6-9, the rotating seal comprises an upper sealingmember 610 and a lower sealing member 620. As shown in FIG. 6, whenbiased together, the contact of the sealing members creates a pluralityof annular seals. A first seal 700 is formed between sealing surfaces612 and 622, and a second seal 702 is formed between sealing surfaces613 and 622. As shown in FIGS. 6, 7, and 9, the sealing face of theupper sealing member 610 is formed into two sealing surfaces 612 and 613as lands surrounding a groove 618. The groove forms the upper boundariesof an annular space 710 between the concentric seals 700, 702. Thegroove can be cut from or molded into the upper sealing member asdesired.

In the embodiment depicted in FIGS. 6-9, the sealing face of the lowersealing member 620 is not formed into lands and grooves; rather, thesealing surface 622 forms the plurality of concentric seals incombination with the sealing surfaces 612 and 613, and forms the annularspace in combination with the groove 618. In alternative configurationsof the rotating seal, the lower sealing member can include thetopography of lands and grooves and the upper sealing member can beplanar. In still other embodiments, both the upper and the lower sealingmembers can include lands and grooves. The sealing surfaces preferablyare planar, although other geometries also can be used provided that aclose fit can be achieved between stationary and rotating members of therotating seal.

The upper and lower sealing members 610, 620 also each define axialopenings 619 and 629, respectively. Upon assembly of the sealing membersin axial alignment, the axial openings, the first seal, the annularspace, and the second seal are positioned concentrically relative toeach other.

The annular space 710 can be in communication with the externalenvironment, and preferably is in gaseous communication through thechannel 616. The channel can be formed in either of both of the sealingmembers 610, 620. In preferred embodiments the annular space 710constitutes a sterile chamber. Further seals, separated by additionalannular spaces, may also be included in the rotating seal apparatus.

The rotating seal apparatus depicted in FIGS. 5-9 also includes a body630 having ports 632, 634 and 636 which serve as inlets and/or outletsfor material passing into and out of a processing container to which therotating seal apparatus is mounted. The first port 632 traverses theaxial opening of the rotating seal apparatus, terminating at plug 690.The first port preferably serves as an inlet into the processingcontainer for cells which are to be processed. The first portadditionally serves as the outlet for processed cell following theexecution of processing steps. The first port can be connected to anumber of tubes, fluid handling manifolds, valves etc. as will be knownto one of ordinary skill in the art.

The fluid port 636 is in fluid communication with the annular space 638bounded by the exterior surface of the first port and the walls of theaxial openings 619, 629, 689, 699 of the upper sealing member 610, lowersealing member 620, base 680 and plug 690. The fluid port 636 connectsto the annular space below. In certain embodiments, the fluid port 636and annular space 638 are used for passage of processing materials suchas wash solutions, buffers, enzymes and the like into the processingcontainer. The fluid port 636 and annular space 638 also are used forpassage of waste materials out of the processing container. This outletfunction also serves a temperature regulation function. As the sealingmembers of the rotating seal apparatus turn against each other, localfrictional heating of the rotating seal apparatus above room temperatureoccurs. Passage of waste materials, which are at temperatures at orbelow room temperature, out of the processing container through theannular space 638 and fluid port 636 contact the first port 632 andthereby lower the temperature of the first port. The cooled first portdoes not heat cells as an uncooled port would upon passage of processedcells out of the processing container through the first port. As withthe first port, the fluid port can be connected to a number of tubes,fluid handling manifolds, valves etc. as will be known to one ofordinary skill in the art.

The gas port 634 is in gaseous communication with the annular space 710between the concentrically spaced seals 700, 702. The gas portpreferably serves as the inlet for providing sterile air (or other gas)to pressurize the annular space 710. The gas port can be connected to anumber of tubes, filters, valves etc. for providing a sterile supply ofgas as will be known to one of ordinary skill in the art.

The base 680 and plug 690 fit together as depicted in FIG. 6. A singleunitary base/plug combination also could be used as desired. The base680 serves both as a mount for the lower seal member 620 and as a mountfor the shield clamp 670 by means of the flange 682 and protrusion 684.The base is mounted on the processing container to provide fluidcommunication of the first port 632 and the fluid port 636 with theinterior of the processing container. A plurality of mounts 686 can passthrough sealed portions of the processing container can be mounted onthe chuck of a centrifuge to communicate rotation of the centrifugechuck to the base, processing container and lower seal member of therotating seal apparatus. Other means of securing the rotating sealapparatus and processing container to the centrifuge for providingrotation to the processing container are well known to one of ordinaryskill in the art.

The spring 640 is depicted in FIGS. 6-9, and comprises a hollowgenerally cylindrical-shaped elastic member having bowed sides. Thespring is disposed between the header shield top 660 and the body 630.As depicted, the spring is provided with flanges 642, 644 at its upperand lower ends. The lower flange 644 fits into an annular recess 631formed in the body. The top flange 642 fits against the header shieldtop. Upon assembly of the rotating seal apparatus by snapping the headershield clamp against the base, the spring is deflected from a firstposition to a second position which provides a “pre-load” of contactforces to the seal members. When the rotating seal apparatus is enclosedin a centrifuge, the spring can be deflected to a third position ofgreater deflection which provides an increased contact force to the sealmembers, thereby creating an enhanced seal.

In contrast to helical springs, the cylindrical spring of the inventionprovides a constant biasing force over a wide range of compression. Thespring has a height h which describes the axis of deflection orcompression, a width w which describes the diameter of the spring innondeflected or deflected positions, an thickness t and an arc a. Theheight, when the spring compressed from the first position, is reducedfrom h₁, to h₂. Similarly, the spring width is increased on compressionfrom w₁ to w₂. The spring provides constant biasing force over a Δh ofat least 10%, preferably at least 20%, more preferably at least 30% andmost preferably at least 50%. Further, the spring provides constantbiasing force over a Δw of at least 1%, preferably at least 2%, morepreferably at least 5% and most preferably at least 10%. The range ofcompression over which the biasing force is constant also can bedescribed by the ratio of Δh:Δw, wherein the spring experiences arelatively large Δw for a corresponding Δh. The thickness t of thespring should not be too great as to hinder the bowing of the cylindersides on compression of the spring. A range of thicknesses and arcs willbe useful to provide proper bowing; these ranges can easily bedetermined by one of ordinary skill in the art with no more than routineexperimentation, and may depend on the particular elastomeric materialchosen for manufacture of the spring. The appropriate thickness and arcscan be expressed in terms of ratios of h:t and h:a, when h, t, and a aremeasured in deflected or nondeflected positions.

The rotating seal apparatus of the invention may be validated as“closed” devices, and thereby produce product with longer shelf lifethan prior art rotating seal devices. A second annular seal providedcircumferentially around the first or inner seal provides furtherassurance of seal integrity. To still further promote the sterility ofthe interior of the seal and processing container, the annular space 710can be filled with sterile air and, further, a pressure differential maybe created such that the sterile air in the annular space is at apressure higher than the pressure in the surrounding chamber formed bythe header shield. Therefore, the flow pattern of the hydrodynamic filmmay be directed away from the sterile interior and toward the spacesexterior to the rotating seals. Further, the chamber formed by theheader shield may be provided with a steady supply of sterile air at apressure lower than that in the annular space 710 but higher thanambient pressure. This “double redundancy” of the two surroundingsterile chambers at graduating pressures is theoretically analogous tothat used in the design of clean rooms for sterile filing ofpharmaceuticals.

The annular space 710 can be filled with a gas or liquid; preferably,the gas or liquid is substantially sterile. The enclosed space therebycreates a barrier to microbes or other particulate materials passinginto or out of the interior of the cell processing system. The gas orliquid may be introduced into the enclosed space via a channel whichpasses through or between the upper and lower elements. For example,referring to FIG. 6, air can be pumped through a 0.2 micron filter toassure sterility, and then be pumped through the gas port 634 to thechannel 616 and into the annular space 710. Optionally the annular space638 formed between the inner seal 700 and the first port 632 can bepressurized, for example when the annular space 638 is not conveyingreagents into the processing container 604 or waste liquids out of theprocessing container. Preferably the annular space 710 is pressurizedwith sterile air at pressure slightly above atmospheric pressure. Forexample, it has been determined that an air pressure of approximately0.25 PSIG suffices to provide a pressurized environment in the annularspace to enhance the sealing function of the sealing members. Otherpressures and gases can also be employed in similar fashion as will beevident to one of ordinary skill in the art. In alternative embodiments,the annular space is pressurized relative to the exterior and interiorof the rotating seal apparatus by evacuating the exterior and/orinterior (e.g. the space inside the header shield and/or the annularspace 638, respectively) by means of a vacuum pump or other device whichcreates a pressure differential.

In certain embodiments of the invention, the sterile air may be providedfrom a pressurized tank that uses a precise pressure regulating valve toreduce the tank pressure to a level that is slightly positive relativeto ambient pressures (e.g. 0.25 PSIG). A computer software controlled“watchdog circuit” may be placed in communication with the annular space710 to indicate, in a detectable manner, if and when undesirablepressure levels in the interior of the cell processing system occur.Furthermore, alterations in pressure in the annular space, detectable bya pressure monitor, may alert a system operator that one of the sealingelements has been breached and/or the barrier function of the annularspace has been disrupted.

A second redundant sterile chamber can be created by the header shieldassembly (shield top, shield bottom and shield clamp) that surroundsboth the first and the second seal members. Sterile air may be suppliedto this chamber at a pressure that is less than that of the annularspace between the seals but greater than the surrounding ambientcondition. The flow of air is from areas of higher pressure to areas oflower pressure. Therefore, the flow of sterile air may be directed fromthe inside of the seal and in an outward direction. Potential microbialcontamination may thus be swept away from the sterile interior of theseal by this flow vector.

A serpentine seal 676 is formed between the close tolerance of theopposing flanges 672, 652 of the shield bottom and shield clamp. Theserpentine seal may create shear forces between the surfaces of theflanges which prevent particulate material from the outside the shieldfrom entering the shield and thus the seal assembly. In general, theserpentine seal acts as a physical barrier, if not a seal, tocontaminants external to the rotating seal apparatus.

In additional embodiments, the rotating seal apparatus can be formed oftwo concentric lip seals or two concentric barrel seals. Between lipseals or barrel seals is an annular space analogous to annular space710. The annular space is in communication with a source of gas orliquid (e.g, sterile pressurized air). Additional seal types will beknown to one of ordinary skill in the art.

In operation, the rotating seal apparatus is provided as a preassembleddevice, properly preloaded by spring biasing force to create sealsbetween the upper and lower sealing members. The rotating seal apparatusis placed in a cell processing system centrifugal device, for example bymounting it on a centrifuge chuck by the mounts 686. Closing thecentrifugal device causes the compression of the spring to a thirdposition which forces the seals into closer contact than the preloadcontact and maintains the close contact during rotation. The ports 632,634 and 636 are joined to an appropriate set of tubes, optionally viaconnectors, to provide cells, processing materials, sterile air, etc. tothe rotating seal apparatus and processing container. Upon rotation ofthe centrifugal device, the upper seal member, body, header shield topand bottom remain stationary and the lower seal member, base (andattached processing container), and header shield clamp rotate while theintegrity of the seals are maintained.

The sealing surfaces of the upper and lower sealing members can beformed or fabricated of a variety of materials well known to one ofordinary skill in the art. Suitable materials include ceramics, carbonphenolic, graphite and graphite derivatives, lubricious plasticmaterials such as nylon, delrin, teflon, rulon, bronze and alloysthereof, stainless steel, carbon nitrites, etc. The sealing members canbe manufactured as a single piece or as a separate sealing portions andsupport portions of the sealing member. The sealing members can bemanufactured, for example, by injection molding or other method offabrication, followed by making the sealing surfaces flat (e.g. bygrinding or lapping) and polishing. The sealing members thus treatedhave sealing surfaces which when contacted essentially prevent fluidpassage. Preferred materials include ceramics and carbon phenoliccompounds. In a preferred embodiment, the upper and lower sealingelements are formed of ceramic which is lapped and polished.

Other parts of the apparatus are constructed of various polymericmaterials which preferably are FDA-approved for medical devices. Theheader shield top 660, the header shield bottom 650 and the headershield clamp 670 are preferably constructed of high impact polystyrene(HIPS), although any rigid plastic known to one of ordinary skill in theart which has some elastomeric properties can be used. The body 630 andthe base 680 are preferably constructed of polycarbonate which providesgood strength and stability. Other like materials can also be used.

The spring 640 is constructed of an elastomeric material, and preferablyis constructed of a medium durometer silicon material such as thermosetsilicon or liquid injection molding silicon. One also could use variousrubber materials for the spring, preferably materials which are FDAapproved for medical devices.

The present invention may be used in a variety of cell and cell elementprocessing procedures, including collection and/or washing or red bloodcells, platelets, lymphocytes, granulocytes, monocytes, and stem cells(e.g., from peripheral blood, bone marrow, or cord blood), as well asother methods such as viral inactivation. In preferred embodiments, thecell processing system may be used in methods of enzymaticallyconverting blood type. Methods of converting blood type are, forexample, set forth in U.S. Pat. Nos. 4,330,619 and 4,609,627 byGoldstein. Other uses for the rotating seal portion of the apparatuswill be known to one of ordinary skill in the art.

EQUIVALENTS

Those skilled in the art will recognize, or be able to ascertain usingno more than routine experimentation, many equivalents to the specificembodiments of the invention described herein. Such equivalents areintended to be encompassed by the following claims.

All references disclosed herein are incorporated by reference in theirentirety.

What is claimed is:
 1. A seal apparatus comprising: a body comprising afirst portion and a second portion, wherein an axially aligned firstopening acting as a first port is positioned through the first portionand the second portion, and wherein the first portion includes a recessand a second opening acting as a second port positioned adjacent andparallel to the first port opening; a first annular rotating seal memberpositioned within the recess, the first annular rotating seal memberhaving a non-sealing face, and a sealing face which defines a pluralityof concentrically spaced annular sealing surfaces having an annularspace therebetween, the member further defining an axial opening, and asecond annular rotating seal member having a non-sealing face, and asealing face which defines at least one annular sealing surface, themember further defining an axial opening, wherein the first annularrotating seal member and the second annular rotating seal member areaxially aligned, the annular sealing surfaces of the first annularrotating seal member and the second annular rotating seal member areplaced in contact to form a plurality of spaced apart seals, and atleast one of the non-sealing faces of the first annular rotating sealmember and the second annular rotating seal member define a channel ingaseous communication with said annular space and with the secondopening of the first portion of the body.
 2. The seal apparatus of claim1, wherein the annular sealing surfaces are substantially planar.
 3. Theseal apparatus of claim 1, wherein the annular sealing surfaces of thefirst annular rotating seal member and the second annular rotating sealmember are biased together by a bias element.
 4. The seal apparatus ofclaim 3, wherein the bias element is an elastomeric spring element. 5.The seal apparatus of claim 1, wherein the annular sealing surfaces ofthe first annular rotating seal member and the second annular rotatingseal member are formed of a material selected from the group consistingof ceramics and carbon phenolic.
 6. The seal apparatus of claim 5,wherein the annular sealing surfaces of the first annular rotating sealmember and the second annular rotating seal member are formed ofceramic.
 7. The seal apparatus of claim 1, further comprising a basehaving an axial opening and a processing container having a top definingan axial opening, the base mounted in axial alignment on the top of theprocessing container, the second annular rotating seal member mounted inaxial alignment on the top surface of the base, wherein the first portis in fluid communication with the interior of the processing chamber.8. The seal apparatus of claim 7, wherein the first port extends throughthe axial openings of the first and second annular rotating seal membersand the base.
 9. The seal apparatus of claim 8, wherein the body furthercomprises a fluid port in fluid communication with a space defined bythe first port, the first and second annular rotating seal members andthe axial openings of the base.
 10. The seal apparatus of claim 7,further comprising an outer shield defining a space between the outershield and the body, the base and the first and second annular rotatingseal members.
 11. The seal apparatus of claim 10, wherein the outershield comprises a shield top, a shield bottom and a shield clamp,wherein the shield top is releasably mounted on the shield bottom, andwherein the shield bottom and the shield clamp have overlapping flangeswhich form a serpentine seal.
 12. The seal apparatus of claim 11,further comprising an elastomeric spring element disposed between theshield top and the body, wherein the clamp is movable between a firstposition and a second position wherein the shield clamp is engaged withthe base, wherein the spring element is compressed when the shield clampis in the second position.